of the eligibles desired the three highest in grade of that sex shall be certified:  Provided, That the eligibles upon any register who have been allowed preference under section 1754 of the Revised Statutes shall be certified, according to their grade, before all other eligibles thereon:  Provided further, That no certification for an appointment shall be made under this clause while there are persons in the district in which any vacancy may exist, who have been removed from the service in that district on account of a reduction of the force or otherwise, who are eligible for reinstatement under Internal-Revenue Rule VII, and who are willing to reenter the service by reinstatement.  Every collector of internal revenue shall keep a list of all such persons in his office, and said persons shall have preference for reinstatement to the service in the order of their separation therefrom.

  (c) No eligible shall be certified more than three times.

2.  Of the three names certified to him the Commissioner of Internal Revenue shall select one, and may select more than one if more than one vacancy exists at the time the certification is made.  If the vacancy is in the class of clerk, the Commissioner shall certify the name of the person selected by him to the collector of the district in which the vacancy occurs and the collector shall make the appointment.  If the vacancy is in the storekeepers’, gaugers’, or storekeepers and gaugers’ class, the Commissioner of Internal Revenue shall certify the name to the Secretary of the Treasury with his recommendation that the person whose name is thus certified be appointed:  Provided, That if any objection is made under section 3 of General Rule IV to any eligible certified, and is sustained by the Commission, another eligible shall be certified in the place of the one objected to.

3.  Each person thus selected for appointment shall be notified, and upon indicating his acceptance shall be appointed for a probationary period of six months, at the end of which period, if his conduct and capacity be satisfactory to the appointing officer, he shall receive absolute appointment; but if his conduct and capacity be not satisfactory to said officer he shall be so notified, and this notification shall be his discharge from the service:  Provided, That any probationer may be discharged during probation for misconduct or evident unfitness or incapacity.

4.  The Commissioner of Internal Revenue shall require the collector under whom a probationer is serving to carefully observe and report in writing upon the services rendered by and the character and qualifications of such probationer as to punctuality, industry, habits, ability, and adaptability.  These reports shall be preserved on file in the office of the collector, and copies thereof shall be filed with the Commissioner of Internal Revenue for such disposition as the Secretary of the Treasury